1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * TI LP855x Backlight Driver
4 *
5 * Copyright (C) 2011 Texas Instruments
6 */
7
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/i2c.h>
11 #include <linux/backlight.h>
12 #include <linux/delay.h>
13 #include <linux/err.h>
14 #include <linux/of.h>
15 #include <linux/platform_data/lp855x.h>
16 #include <linux/pwm.h>
17 #include <linux/regulator/consumer.h>
18
19 /* LP8550/1/2/3/6 Registers */
20 #define LP855X_BRIGHTNESS_CTRL 0x00
21 #define LP855X_DEVICE_CTRL 0x01
22 #define LP855X_EEPROM_START 0xA0
23 #define LP855X_EEPROM_END 0xA7
24 #define LP8556_EPROM_START 0xA0
25 #define LP8556_EPROM_END 0xAF
26
27 /* LP8555/7 Registers */
28 #define LP8557_BL_CMD 0x00
29 #define LP8557_BL_MASK 0x01
30 #define LP8557_BL_ON 0x01
31 #define LP8557_BL_OFF 0x00
32 #define LP8557_BRIGHTNESS_CTRL 0x04
33 #define LP8557_CONFIG 0x10
34 #define LP8555_EPROM_START 0x10
35 #define LP8555_EPROM_END 0x7A
36 #define LP8557_EPROM_START 0x10
37 #define LP8557_EPROM_END 0x1E
38
39 #define DEFAULT_BL_NAME "lcd-backlight"
40 #define MAX_BRIGHTNESS 255
41
42 enum lp855x_brightness_ctrl_mode {
43 PWM_BASED = 1,
44 REGISTER_BASED,
45 };
46
47 struct lp855x;
48
49 /*
50 * struct lp855x_device_config
51 * @pre_init_device: init device function call before updating the brightness
52 * @reg_brightness: register address for brigthenss control
53 * @reg_devicectrl: register address for device control
54 * @post_init_device: late init device function call
55 */
56 struct lp855x_device_config {
57 int (*pre_init_device)(struct lp855x *);
58 u8 reg_brightness;
59 u8 reg_devicectrl;
60 int (*post_init_device)(struct lp855x *);
61 };
62
63 struct lp855x {
64 const char *chipname;
65 enum lp855x_chip_id chip_id;
66 enum lp855x_brightness_ctrl_mode mode;
67 struct lp855x_device_config *cfg;
68 struct i2c_client *client;
69 struct backlight_device *bl;
70 struct device *dev;
71 struct lp855x_platform_data *pdata;
72 struct pwm_device *pwm;
73 struct regulator *supply; /* regulator for VDD input */
74 struct regulator *enable; /* regulator for EN/VDDIO input */
75 };
76
lp855x_write_byte(struct lp855x * lp,u8 reg,u8 data)77 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
78 {
79 return i2c_smbus_write_byte_data(lp->client, reg, data);
80 }
81
lp855x_update_bit(struct lp855x * lp,u8 reg,u8 mask,u8 data)82 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
83 {
84 int ret;
85 u8 tmp;
86
87 ret = i2c_smbus_read_byte_data(lp->client, reg);
88 if (ret < 0) {
89 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
90 return ret;
91 }
92
93 tmp = (u8)ret;
94 tmp &= ~mask;
95 tmp |= data & mask;
96
97 return lp855x_write_byte(lp, reg, tmp);
98 }
99
lp855x_is_valid_rom_area(struct lp855x * lp,u8 addr)100 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
101 {
102 u8 start, end;
103
104 switch (lp->chip_id) {
105 case LP8550:
106 case LP8551:
107 case LP8552:
108 case LP8553:
109 start = LP855X_EEPROM_START;
110 end = LP855X_EEPROM_END;
111 break;
112 case LP8556:
113 start = LP8556_EPROM_START;
114 end = LP8556_EPROM_END;
115 break;
116 case LP8555:
117 start = LP8555_EPROM_START;
118 end = LP8555_EPROM_END;
119 break;
120 case LP8557:
121 start = LP8557_EPROM_START;
122 end = LP8557_EPROM_END;
123 break;
124 default:
125 return false;
126 }
127
128 return addr >= start && addr <= end;
129 }
130
lp8557_bl_off(struct lp855x * lp)131 static int lp8557_bl_off(struct lp855x *lp)
132 {
133 /* BL_ON = 0 before updating EPROM settings */
134 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
135 LP8557_BL_OFF);
136 }
137
lp8557_bl_on(struct lp855x * lp)138 static int lp8557_bl_on(struct lp855x *lp)
139 {
140 /* BL_ON = 1 after updating EPROM settings */
141 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
142 LP8557_BL_ON);
143 }
144
145 static struct lp855x_device_config lp855x_dev_cfg = {
146 .reg_brightness = LP855X_BRIGHTNESS_CTRL,
147 .reg_devicectrl = LP855X_DEVICE_CTRL,
148 };
149
150 static struct lp855x_device_config lp8557_dev_cfg = {
151 .reg_brightness = LP8557_BRIGHTNESS_CTRL,
152 .reg_devicectrl = LP8557_CONFIG,
153 .pre_init_device = lp8557_bl_off,
154 .post_init_device = lp8557_bl_on,
155 };
156
157 /*
158 * Device specific configuration flow
159 *
160 * a) pre_init_device(optional)
161 * b) update the brightness register
162 * c) update device control register
163 * d) update ROM area(optional)
164 * e) post_init_device(optional)
165 *
166 */
lp855x_configure(struct lp855x * lp)167 static int lp855x_configure(struct lp855x *lp)
168 {
169 u8 val, addr;
170 int i, ret;
171 struct lp855x_platform_data *pd = lp->pdata;
172
173 switch (lp->chip_id) {
174 case LP8550:
175 case LP8551:
176 case LP8552:
177 case LP8553:
178 case LP8556:
179 lp->cfg = &lp855x_dev_cfg;
180 break;
181 case LP8555:
182 case LP8557:
183 lp->cfg = &lp8557_dev_cfg;
184 break;
185 default:
186 return -EINVAL;
187 }
188
189 if (lp->cfg->pre_init_device) {
190 ret = lp->cfg->pre_init_device(lp);
191 if (ret) {
192 dev_err(lp->dev, "pre init device err: %d\n", ret);
193 goto err;
194 }
195 }
196
197 val = pd->initial_brightness;
198 ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
199 if (ret)
200 goto err;
201
202 val = pd->device_control;
203 ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
204 if (ret)
205 goto err;
206
207 if (pd->size_program > 0) {
208 for (i = 0; i < pd->size_program; i++) {
209 addr = pd->rom_data[i].addr;
210 val = pd->rom_data[i].val;
211 if (!lp855x_is_valid_rom_area(lp, addr))
212 continue;
213
214 ret = lp855x_write_byte(lp, addr, val);
215 if (ret)
216 goto err;
217 }
218 }
219
220 if (lp->cfg->post_init_device) {
221 ret = lp->cfg->post_init_device(lp);
222 if (ret) {
223 dev_err(lp->dev, "post init device err: %d\n", ret);
224 goto err;
225 }
226 }
227
228 return 0;
229
230 err:
231 return ret;
232 }
233
lp855x_pwm_ctrl(struct lp855x * lp,int br,int max_br)234 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
235 {
236 unsigned int period = lp->pdata->period_ns;
237 unsigned int duty = br * period / max_br;
238 struct pwm_device *pwm;
239
240 /* request pwm device with the consumer name */
241 if (!lp->pwm) {
242 pwm = devm_pwm_get(lp->dev, lp->chipname);
243 if (IS_ERR(pwm))
244 return;
245
246 lp->pwm = pwm;
247
248 /*
249 * FIXME: pwm_apply_args() should be removed when switching to
250 * the atomic PWM API.
251 */
252 pwm_apply_args(pwm);
253 }
254
255 pwm_config(lp->pwm, duty, period);
256 if (duty)
257 pwm_enable(lp->pwm);
258 else
259 pwm_disable(lp->pwm);
260 }
261
lp855x_bl_update_status(struct backlight_device * bl)262 static int lp855x_bl_update_status(struct backlight_device *bl)
263 {
264 struct lp855x *lp = bl_get_data(bl);
265 int brightness = bl->props.brightness;
266
267 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
268 brightness = 0;
269
270 if (lp->mode == PWM_BASED)
271 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
272 else if (lp->mode == REGISTER_BASED)
273 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
274
275 return 0;
276 }
277
278 static const struct backlight_ops lp855x_bl_ops = {
279 .options = BL_CORE_SUSPENDRESUME,
280 .update_status = lp855x_bl_update_status,
281 };
282
lp855x_backlight_register(struct lp855x * lp)283 static int lp855x_backlight_register(struct lp855x *lp)
284 {
285 struct backlight_device *bl;
286 struct backlight_properties props;
287 struct lp855x_platform_data *pdata = lp->pdata;
288 const char *name = pdata->name ? : DEFAULT_BL_NAME;
289
290 memset(&props, 0, sizeof(props));
291 props.type = BACKLIGHT_PLATFORM;
292 props.max_brightness = MAX_BRIGHTNESS;
293
294 if (pdata->initial_brightness > props.max_brightness)
295 pdata->initial_brightness = props.max_brightness;
296
297 props.brightness = pdata->initial_brightness;
298
299 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
300 &lp855x_bl_ops, &props);
301 if (IS_ERR(bl))
302 return PTR_ERR(bl);
303
304 lp->bl = bl;
305
306 return 0;
307 }
308
lp855x_get_chip_id(struct device * dev,struct device_attribute * attr,char * buf)309 static ssize_t lp855x_get_chip_id(struct device *dev,
310 struct device_attribute *attr, char *buf)
311 {
312 struct lp855x *lp = dev_get_drvdata(dev);
313
314 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
315 }
316
lp855x_get_bl_ctl_mode(struct device * dev,struct device_attribute * attr,char * buf)317 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
318 struct device_attribute *attr, char *buf)
319 {
320 struct lp855x *lp = dev_get_drvdata(dev);
321 char *strmode = NULL;
322
323 if (lp->mode == PWM_BASED)
324 strmode = "pwm based";
325 else if (lp->mode == REGISTER_BASED)
326 strmode = "register based";
327
328 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
329 }
330
331 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
332 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
333
334 static struct attribute *lp855x_attributes[] = {
335 &dev_attr_chip_id.attr,
336 &dev_attr_bl_ctl_mode.attr,
337 NULL,
338 };
339
340 static const struct attribute_group lp855x_attr_group = {
341 .attrs = lp855x_attributes,
342 };
343
344 #ifdef CONFIG_OF
lp855x_parse_dt(struct lp855x * lp)345 static int lp855x_parse_dt(struct lp855x *lp)
346 {
347 struct device *dev = lp->dev;
348 struct device_node *node = dev->of_node;
349 struct lp855x_platform_data *pdata;
350 int rom_length;
351
352 if (!node) {
353 dev_err(dev, "no platform data\n");
354 return -EINVAL;
355 }
356
357 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
358 if (!pdata)
359 return -ENOMEM;
360
361 of_property_read_string(node, "bl-name", &pdata->name);
362 of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
363 of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
364 of_property_read_u32(node, "pwm-period", &pdata->period_ns);
365
366 /* Fill ROM platform data if defined */
367 rom_length = of_get_child_count(node);
368 if (rom_length > 0) {
369 struct lp855x_rom_data *rom;
370 struct device_node *child;
371 int i = 0;
372
373 rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL);
374 if (!rom)
375 return -ENOMEM;
376
377 for_each_child_of_node(node, child) {
378 of_property_read_u8(child, "rom-addr", &rom[i].addr);
379 of_property_read_u8(child, "rom-val", &rom[i].val);
380 i++;
381 }
382
383 pdata->size_program = rom_length;
384 pdata->rom_data = &rom[0];
385 }
386
387 lp->pdata = pdata;
388
389 return 0;
390 }
391 #else
lp855x_parse_dt(struct lp855x * lp)392 static int lp855x_parse_dt(struct lp855x *lp)
393 {
394 return -EINVAL;
395 }
396 #endif
397
lp855x_probe(struct i2c_client * cl,const struct i2c_device_id * id)398 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
399 {
400 struct lp855x *lp;
401 int ret;
402
403 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
404 return -EIO;
405
406 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
407 if (!lp)
408 return -ENOMEM;
409
410 lp->client = cl;
411 lp->dev = &cl->dev;
412 lp->chipname = id->name;
413 lp->chip_id = id->driver_data;
414 lp->pdata = dev_get_platdata(&cl->dev);
415
416 if (!lp->pdata) {
417 ret = lp855x_parse_dt(lp);
418 if (ret < 0)
419 return ret;
420 }
421
422 if (lp->pdata->period_ns > 0)
423 lp->mode = PWM_BASED;
424 else
425 lp->mode = REGISTER_BASED;
426
427 lp->supply = devm_regulator_get(lp->dev, "power");
428 if (IS_ERR(lp->supply)) {
429 if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
430 return -EPROBE_DEFER;
431 lp->supply = NULL;
432 }
433
434 lp->enable = devm_regulator_get_optional(lp->dev, "enable");
435 if (IS_ERR(lp->enable)) {
436 ret = PTR_ERR(lp->enable);
437 if (ret == -ENODEV) {
438 lp->enable = NULL;
439 } else {
440 if (ret != -EPROBE_DEFER)
441 dev_err(lp->dev, "error getting enable regulator: %d\n",
442 ret);
443 return ret;
444 }
445 }
446
447 if (lp->supply) {
448 ret = regulator_enable(lp->supply);
449 if (ret < 0) {
450 dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
451 return ret;
452 }
453 }
454
455 if (lp->enable) {
456 ret = regulator_enable(lp->enable);
457 if (ret < 0) {
458 dev_err(lp->dev, "failed to enable vddio: %d\n", ret);
459 goto disable_supply;
460 }
461
462 /*
463 * LP8555 datasheet says t_RESPONSE (time between VDDIO and
464 * I2C) is 1ms.
465 */
466 usleep_range(1000, 2000);
467 }
468
469 i2c_set_clientdata(cl, lp);
470
471 ret = lp855x_configure(lp);
472 if (ret) {
473 dev_err(lp->dev, "device config err: %d", ret);
474 goto disable_vddio;
475 }
476
477 ret = lp855x_backlight_register(lp);
478 if (ret) {
479 dev_err(lp->dev,
480 "failed to register backlight. err: %d\n", ret);
481 goto disable_vddio;
482 }
483
484 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
485 if (ret) {
486 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
487 goto disable_vddio;
488 }
489
490 backlight_update_status(lp->bl);
491
492 return 0;
493
494 disable_vddio:
495 if (lp->enable)
496 regulator_disable(lp->enable);
497 disable_supply:
498 if (lp->supply)
499 regulator_disable(lp->supply);
500
501 return ret;
502 }
503
lp855x_remove(struct i2c_client * cl)504 static int lp855x_remove(struct i2c_client *cl)
505 {
506 struct lp855x *lp = i2c_get_clientdata(cl);
507
508 lp->bl->props.brightness = 0;
509 backlight_update_status(lp->bl);
510 if (lp->enable)
511 regulator_disable(lp->enable);
512 if (lp->supply)
513 regulator_disable(lp->supply);
514 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
515
516 return 0;
517 }
518
519 static const struct of_device_id lp855x_dt_ids[] = {
520 { .compatible = "ti,lp8550", },
521 { .compatible = "ti,lp8551", },
522 { .compatible = "ti,lp8552", },
523 { .compatible = "ti,lp8553", },
524 { .compatible = "ti,lp8555", },
525 { .compatible = "ti,lp8556", },
526 { .compatible = "ti,lp8557", },
527 { }
528 };
529 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
530
531 static const struct i2c_device_id lp855x_ids[] = {
532 {"lp8550", LP8550},
533 {"lp8551", LP8551},
534 {"lp8552", LP8552},
535 {"lp8553", LP8553},
536 {"lp8555", LP8555},
537 {"lp8556", LP8556},
538 {"lp8557", LP8557},
539 { }
540 };
541 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
542
543 static struct i2c_driver lp855x_driver = {
544 .driver = {
545 .name = "lp855x",
546 .of_match_table = of_match_ptr(lp855x_dt_ids),
547 },
548 .probe = lp855x_probe,
549 .remove = lp855x_remove,
550 .id_table = lp855x_ids,
551 };
552
553 module_i2c_driver(lp855x_driver);
554
555 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
556 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
557 MODULE_LICENSE("GPL");
558
